Switch unit



oct. 2, 1945. A B. E. SHAW I 2,885,887A

` swITcH UNIT l Filed June 9, 1942 55g 54014/ y/zfmw A mar/ggf PatentedOct. `2, 1945 SWITCH UNIT BurtonE. Shaw, Bristol, Ind., assigner to PennElectric Switch Co., Goshen, Ind., a corporation of Iowa ApplicationJune 9, 1942, Serial No. 446,348

8 Claims.

Mypresent invention has to do with a switch unit of the generalcharacter shown in my issued patents, No. 2,111,816, dated March 22,1938, No. 2,170,341, dated August 22,- 1939, and No. 2,229,022, datedJanuary 14, 1941.

One object of my present invention is to pro vide certain improvementsover my prior patents, particularly with respect to certainconstructional features which improve the contact action and secureother desirable results.

More particularly, it is my object to provide a switch unit wherein amagnet and armature means is used to secure snap action, and to also aida leaf spring in holding a movable contact in engagement with astationary contact, thereby providing ,the necessary pressure forpushing through a lm of dirt or the like on the contacts, which, ofcourse, is especially desirable in connection with the control of lowvoltage circuits.I

Another object is to provide a positive two-way lost motion connectionbetween an armature or switch arm and a movable contact to secure theadvantagev of the magnetic pull being imposed on the movable contactwith respect -to the stationary contact, and to also provide for somemovement of the switch arm in a switch opening direction before themovable contact is separated from the stationary contact, therebyproviding for a hammer break of the circuit.

Still another'object is to provide an arrangement wherein the contactsconstitute a stop for the armature in' its position adjacent the magnet,and a novel and simple arrangement for adjusting the differentialof'operation of the switch through an adjustment of the connectionbetween the switch arm and the movable contact.

Still a further object is to provide a leaf spring connection betweenthe switch arm and an actuating element to eliminate the loose spiralspring shown in my former patents, and to provide a simple adjustingmeans for stopping the switch arm in its open circuit position by abendable buttery portion of the switch arm.

With these and other objects in view, my in.- vention consists in theconstruction, arrangement and combination of the various parts of'mydevice whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims and illustrated intheaccom` panying drawing, in which:

Figure,Y 1 is an enlarged side elevation of a switch unit embodying myinvention, showing the housing in section;

Figure 2 is a sectional view on the line 2-2 of Figure 1;

Figure is a sectional view on the line 3-3 of Figure 2 Figure 4 is aside elevation with parts broken away to show the elements of the switchin a different position than Figure 3;

Figure 5 is a perspective view of one end of the switch arm in my switchunit; and

Figure 6 is a sectional view on the line 6-6 of Figure 3, showing aconnection between the switch arm and the movable contact.

On the accompanying drawing I have used the reference numeral I0 toindicate a base. A housing I2 is mounted on the base l0. 'I'he housingand base may be retained in assembled position by screws I3 passingtherethrough and into any suitable supporting surface on which the topof i the base and provided with a retaining nut I8 on its outer end. Aterminal screw 20 is screwed into the terminal sleeve I6 for connectionwith a circuit wire.

A leaf spring 22 is carried by the finger II, a screw 23 being shown forconnecting `the spring to the finger. A movable contact 24 is carried bythe leaf spring 22 and is adapted to coact with a stationary contact 28.'Ihe movable contact is mounted on the leaf Spring 22 by having a shankportion 26 thereof riveted in position. 'I'he stationary contact 28 hasa reduced portion 30 pressed into a second terminal sleeve 32 which, inturn, is retained in position through the base I0 by a retainer nut 34.A second terminal screw 36 is threaded into the'terminal sleeve 32.

A finger-like bracket 38 is mounted on the ter' minal sleeve 32 forretaining a/ U-shaped magnet 40 in a socket 4| of the base I0. Themagnet 40 is adapted to cooperate with armatures 44 formed on a switchor armature arm 42.

The switch arm 42 is pivoted by a pin 4.8 to the two ears of the bracketI4, the pivotal point being intermediate the ends of the switch arm andpreferably at the center of mass thereof so that the switch arm isunaffected by the vibration of a support on which the switch unit ismounted.

l'I'he switch arm 42 has an extension 50 beyond Vthe armature portion 44thereof which passes through an eye of a bracket 48. The bracket 48 issecured yto-the leaf spring 22 as by a rivet 53, and has cross-bars 49and 5I for coaction with opposite faces of the extension D, as willhereinafter be described. An adjusting screw 82 passes through theswitch arm 42 and bears against the Vextension 50 for forcing it tovarious positions with respect to the switch arm 42. Referring to Figure3, it will be noted that the contacts 24 and 28 are engaged, and thatthe extension 58 is engaged .with the cross-piece 49 of the bracket`48.The armature portions. are adjacent the poles of the magnet 48, andtheswitch arm is being normally held in this position against a slightbias of a leaf spring 58. VThe contacts V vthrough engagement at 49-58thereby act as a stop, and the distance of the amature from the magnetmay now be increased by screwing the adjusting screw 52 inwardly, ordecreased by screwing it outwardly. Thereby the differential ofoperation of the switch may be varied, as desired.

The switch arm 42 is provided witha pair of extensions 55 at its endopposite the armature 40,'and these are connected by a cross-piece 51having a stop butterfly-like blade 54 formed thereon. The blade 54 isadapted to engage a surface 56 of the base I0, as shown in Figure 4,when the switch arm is in open circuit position.

The butterfly 54 may be -twisted to change theposition of its cornerwhich v.engages the surface 56 with relation to the switch arm tothereby adjust the open circuit position of the switch arm and theseparated position of the contacts 24 and 28, as desired.

The switch unit illustrated is adapted to be actuated manually or by acondition responsive device through an actuating pin 62 slidable in aboss B3 0f the housing i2. The actuating pin 62 engages a leaf spring 58riveted as at 60 to the switch arm 42.

Practical operation In the operation of my switch structure, assuming,first, the closed circuit position of Figures 1, 3 and 6, the contacts24 and 28'are engaged under the constraint of the leaf spring 22 (whichhas slight initial tension to insure` such engagement).

The magnet 48 is holding the armature 44 in a position adjacent thereto,which, through the di rect connection 45t- 50, imposes the pull of themagnet on the movable contact 24 against the stationary contact 28. downany insulating film on the contacts due to the pull of the magnet inaddition to the slight pull of the spring 22.

LWhen, the actuating element 82` is pushed in-V wardly it will rsttension the spring 58 until the Vtension thereof overcomes the pull ofthe magnet 40 on .thearm 44. Thereupon, Athe armature will Y move awayfrom theV magnet, and, being immediately Yin a weaker magnetic field,the tension builtup in the spring 58 will have an ever increasing effecton the switch arm to throw it toward open circuit position. After theswitch arm moves a slight distance. the extension 50 will pick up thecross-piece 5i of the bracket 48, thereupon separating the contact 24from the contact 28 witha hammer break. The parts will continue to move,due to the tension of the spring 58 and the force ofV momentum, untilthey assume the open circuit position of Figure 4. y The blade 54thereupon engages the surface 58 of the base `|0 vto stop the switch`arm in its open-'circuit This effectively breaksV ASome changes may bemade in the'construction and arrangement of the parts of my devicewithout departing from the real spirit and purpose of my invention, andit is my intention to cover by my claims any modified forms ofstructure, or use of mechanical equivalents, which may be reasonablyincluded within their scope.

I claim as my invention:

l. In a control switch unit, a switch arm having an armature, a magnetcooperating with said armature to constrain. said switch arm towardmovement in one direction, a pairA of contacts, one of Awhich isstationary, a leaf spring having the other contact mounted thereon, saidcontacts, when said leaf spring is in one position, being' engaged andwhen said leaf spring is Vin another position being disengaged, saidswitch arm having means operably engaging said leaf spring to v`move itfrom one of its positions to the other one when said switch arm is movedto one of its positions, said means of engagement being arranged to stopthe switch arm in a predetermined position when said contacts. areengaged, whereupon said armature is thereby spaced a predetermineddistance from said magnet, and the-pull of the magnet on the armatureassists the leaf spring in retaining the contacts engagedand means foradjusting the point of engagementof said switchv arm with respect tosaid leaf spring whereby to vary the distance of the armatur'efrom thema.,- net. f

2. In a. control switch unit, a switch arm hav- Y ing an armature, amagnet cooperating with said armature to constrain said switch armtoward said magnet, means for adjusting the point of en'- gagement ofsaid switch arm with respect to said leaf spring whereby tov vary thedistance-of thet armature from the magnet, said `armature'inrits switchcontact closed position adding its'pressure to'said movable contact inits engagement with said stationary contact.

3. In a switch structure, a magnet, a switch arm pivoted with relationthereto, a leaf spring, a stationary contact, a movable contact mountedon said leaf'spring for cooperation with said stationary contact, meanson said switch arm to engage said leaf spring and thereby Vengage saidcontacts with each other when s aid switch arm is moved toward saidmagnet, said armature being stopped by such engagement of said gcontacts whereby the magnetic pull holds the contacts engaged said lastmeans being adjustable lrelative t0 said switch arm for varying vtheposition of said switch arm relative to said magnet when said contactsare engaged with each other.

4. In a control switch unit, a switch housing assassv including -a base.a pivot bracket thereon, a switch arm pivoted to said pivot bracket, anarmature on said switch arm, a magnet, an operating element extendingfrom said switch housing for moving said switch arm'in a direction forsaid amature to move away from said magnet, a leaf spring connectionbetween said operating element and said switch arm, contacts controlledby said switch arm and located in said switch housing, said contactscomprising a stationary contact and a leaf spring mounted contactnormally engaged with each other, said switch arm having, at a pointbetween said switch arm pivot and said magnet, an operating connectionwith said leaf spring mounted contact to separate said contacts in oneposition of said switch arm and to engage them in the other positionthereof, said contacts in said other position thereof constituting astop for said switch arm in opposition to said magnet whereby the pullof the magnet is multiplied and imposed as a direct holding pressure onsaid contacts.

5. In a control switch unit, a switch housing including a base, a pivotbracket thereon, a switch arm pivoted to said pivot bracket, an armatureon said switch arm, aV magnet. a stop for said switch arm to normallyposition said armature spaced from said magnet, with the magneticpressure imposed directly on the stop said stop comprising circuitcontrolling contacts controlled by said` switch arm and enclosed in saidswitch housing, an operating element extending from said switch housingfor moving said switch arm in a direction for said armature to' moveaway from said magnet, and a leaf spring interposed between saidoperating element and said switch arm and carried by the switch arm.

6. In a control switch, a support, a pair of contacts mounted on saidsupport and normally biased to closed position, a.switch arm pivotedrelative to said support and operative. to engage said contacts witheach other whereupon they constitute a stop for limiting movement ofsaid switch arm in one direction, a magnet, an armature on said switcharm and cooperable with said switch' magnet to secure snap action of thecontrol switch, said switch arm having an extension including across-member and a blade formed thereon, said blade having an edgeengageable with said support to constitute a stop o for said switch armin the other direction, said cross member and blade being twistable forchanging the position of said stop edge of said blade relative to saidswitch arm and thereby changing the position of the switch arm whenstopped in said other direction.

7. In a switch unit, a base, a pair of terminals mounted thereon, astationary contact carried by one of said terminals, a spring bladecarried by the other terminal and having a movable contact carriedthereby and normally constrained to circuit closing coaction with saidstationary contact,

means for disengaging said movable contact from said stationary contactcomprising an armature arm pivoted on said base at substantially thecenter of mass of the armature arm, a magnet cooperating therewith toproduce snap acting movement of said arm, an actuating element fortransmitting movement from a condition responsive device to said arm,said arm having a lost mo tion connection with said spring bladeeffective to cause said contacts when engaged to serve as a positivestop for said armature arm in one drection with the magnetic pullimposed directly on the contacts to keep them engaged and for thearmature arm to move slightly in the opposite direction before pickingup the spring blade and thereupon separating the movable contact fromthe stationary contact.

8. In a switch unit, a base, switch contacts mounted thereon andnormally biased to engage each other, means for separating said switchcontacts from each other comprising a switch arm pivoted on said base,an armature carried by one end of said switch arm, the other end thereofbeing provided with a stop portion which provides additional weight tocounterbalance said armature and which is adapted to engage said base tolimit the position of the switch arm, a magnet mounted on said base andcooperating with said arm to provide snap-acting movement of said switcharm, an actuating element for transmitting movement from a conditionresponsive device to said switch arm, said stop portion of said switcharm being bendable to a different position relative to said switch armwhereby to vary the switch open position of the switch arm with relationto said base.

BURTON E. SHAW.

